From 6355144b8c3514cccc5c2ab4f7c4fd8e76a1a9fc Mon Sep 17 00:00:00 2001
From: hozan23 <hozan23@karyontech.net>
Date: Sun, 23 Jun 2024 15:57:43 +0200
Subject: Fix the issue with message dispatcher and channels

Resolved a previous error where each subscription would create a new
channel with the fixed buffer size. This caused blocking when the
channel buffer was full, preventing the client from handling additional messages.

Now, there is a `subscriptions` struct that holds a queue for receiving
notifications, ensuring the notify function does not block.
---
 jsonrpc/client/subscriptions_test.go | 87 ++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 jsonrpc/client/subscriptions_test.go

(limited to 'jsonrpc/client/subscriptions_test.go')

diff --git a/jsonrpc/client/subscriptions_test.go b/jsonrpc/client/subscriptions_test.go
new file mode 100644
index 0000000..cb5705a
--- /dev/null
+++ b/jsonrpc/client/subscriptions_test.go
@@ -0,0 +1,87 @@
+package client
+
+import (
+	"encoding/json"
+	"sync"
+	"sync/atomic"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSubscriptionsSubscribe(t *testing.T) {
+	bufSize := 100
+	subs := newSubscriptions(bufSize)
+
+	var receivedNotifications atomic.Int32
+
+	var wg sync.WaitGroup
+
+	runSubNotify := func(sub *Subscription) {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for i := 0; i < bufSize; i++ {
+				b, err := json.Marshal(i)
+				assert.Nil(t, err)
+				err = sub.notify(b)
+				assert.Nil(t, err)
+			}
+		}()
+	}
+
+	runSubRecv := func(sub *Subscription) {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			i := 0
+			for nt := range sub.Recv() {
+				var v int
+				err := json.Unmarshal(nt, &v)
+				assert.Nil(t, err)
+				assert.Equal(t, v, i)
+				receivedNotifications.Add(1)
+				i += 1
+				if i == bufSize {
+					break
+				}
+			}
+			sub.stop()
+		}()
+	}
+
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		for i := 0; i < 3; i++ {
+			sub := subs.subscribe(i)
+			runSubNotify(sub)
+			runSubRecv(sub)
+		}
+	}()
+
+	wg.Wait()
+	assert.Equal(t, receivedNotifications.Load(), int32(bufSize*3))
+}
+
+func TestSubscriptionsUnsubscribe(t *testing.T) {
+	bufSize := 100
+	subs := newSubscriptions(bufSize)
+
+	var wg sync.WaitGroup
+
+	sub := subs.subscribe(1)
+	subs.unsubscribe(1)
+
+	_, ok := <-sub.Recv()
+	assert.False(t, ok)
+
+	b, err := json.Marshal(1)
+	assert.Nil(t, err)
+	err = sub.notify(b)
+	if assert.Error(t, err) {
+		assert.ErrorIs(t, err, subscriptionIsClosedErr)
+	}
+
+	wg.Wait()
+}
-- 
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